Rights organisations say that although there are four candidates, the poll cannot be regarded as free and fair.

Human Rights Watch said true political opposition was suppressed and that the government "severely restricts free expression and persecutes independent journalists".

The Organisation for Security and Cooperation in Europe (OSCE) does have a 21-strong team observing the poll, but said comprehensive monitoring was pointless "due to the apparent limited nature of the competition".

Mr Karimov's rule has been marred by the crackdown on opposition in the city of Andijan in 2005.

Government troops opened fire on thousands of demonstrators. Eye witnesses said hundreds of civilians died at a peaceful protest but Mr Karimov insisted the security forces had killed only 189 Islamist militants.

The government has since been accused of many cases of torture.

If you say one wrong thing you can find yourself unemployed or worse, in prison

Uzbek voter

Millions of Uzbeks have gone to live and work abroad.

Mr Karimov has also become more stridently anti-Western amid criticism over Andijan.

In the presidential election of 2000, Mr Karimov's supposed opponent admitted he voted for the Uzbek leader.

The country is rich in energy and resources but its economy is in dire shape says Natalia Antelava.

The media is controlled by the state, the internet is censored and agents of President Karimov's powerful secret services are everywhere, keeping a close watch on every citizen, she says.

Analysts say that the black market is the only functioning economy and that the country depends heavily on the income from an estimated 1.5 million illegal migrants working in Russia and neighbouring Kazakhstan.

Exit polls are prohibited by law, but preliminary results are expected by 1300 GMT on Monday.